Incidence and geographical distribution of downy mildew on maize caused byPeronosclerospora sorghiin Nigeria
作者:
O. M. Olanya,
J. M. Fajemisin,
P. Oyekan,
期刊:
International Journal of Pest Management
(Taylor Available online 1993)
卷期:
Volume 39,
issue 1
页码: 28-34
ISSN:0967-0874
年代: 1993
DOI:10.1080/09670879309371755
出版商: Taylor & Francis Group
关键词: Sorghum downy mildew;Peronosclerospora sorghi;Zea mays L;spatial pattern;Nigeria
数据来源: Taylor
摘要:
Incidence and geographical distribution of downy mildew(Peronosclerospora sorghi)on maize(Zea mays)were determined in a systematic survey of 181 maize fields in the major maize‐growing regions and ecological zones of Nigeria. Downy mildew was observed in the forest and Guinea savanna ecologies, but no disease was detected in other ecologies. Highest levels of disease incidence (63%) were observed in the forest zone, and progressively less disease incidence was found at the southern and northern Guinea savanna zones. Spatial pattern analysis indicated an aggregation and randomness of infected plants in the northern Guinea savanna and the forest zone, respectively. Disease incidence was positively correlated with the presence of downy mildew infected sorghum plants and relative amount of sporulation on infected sorghum(Sorghum bicolor)but negatively correlated with plant age and cropping pattern. Relative sporulation on maize plants was negatively correlated with age of maize plants. Higher levels of disease incidence were observed when the previous crop was either maize or sorghum than when previous crops were cassava, okra, tomatoes, or rice.
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